Fixing PREG_BACKTRACK_LIMIT_ERROR in HTMLPurifier_Filter_ExtractStyleBlocks
[htmlpurifier.git] / library / HTMLPurifier / URISchemeRegistry.php
blob4ac8a0b76e8baec94842b9da2688b9e98aa24a95
1 <?php
3 /**
4 * Registry for retrieving specific URI scheme validator objects.
5 */
6 class HTMLPurifier_URISchemeRegistry
9 /**
10 * Retrieve sole instance of the registry.
11 * @param HTMLPurifier_URISchemeRegistry $prototype Optional prototype to overload sole instance with,
12 * or bool true to reset to default registry.
13 * @return HTMLPurifier_URISchemeRegistry
14 * @note Pass a registry object $prototype with a compatible interface and
15 * the function will copy it and return it all further times.
17 public static function instance($prototype = null)
19 static $instance = null;
20 if ($prototype !== null) {
21 $instance = $prototype;
22 } elseif ($instance === null || $prototype == true) {
23 $instance = new HTMLPurifier_URISchemeRegistry();
25 return $instance;
28 /**
29 * Cache of retrieved schemes.
30 * @type HTMLPurifier_URIScheme[]
32 protected $schemes = array();
34 /**
35 * Retrieves a scheme validator object
36 * @param string $scheme String scheme name like http or mailto
37 * @param HTMLPurifier_Config $config
38 * @param HTMLPurifier_Context $context
39 * @return HTMLPurifier_URIScheme
41 public function getScheme($scheme, $config, $context)
43 if (!$config) {
44 $config = HTMLPurifier_Config::createDefault();
47 // important, otherwise attacker could include arbitrary file
48 $allowed_schemes = $config->get('URI.AllowedSchemes');
49 if (!$config->get('URI.OverrideAllowedSchemes') &&
50 !isset($allowed_schemes[$scheme])
51 ) {
52 return;
55 if (isset($this->schemes[$scheme])) {
56 return $this->schemes[$scheme];
58 if (!isset($allowed_schemes[$scheme])) {
59 return;
62 $class = 'HTMLPurifier_URIScheme_' . $scheme;
63 if (!class_exists($class)) {
64 return;
66 $this->schemes[$scheme] = new $class();
67 return $this->schemes[$scheme];
70 /**
71 * Registers a custom scheme to the cache, bypassing reflection.
72 * @param string $scheme Scheme name
73 * @param HTMLPurifier_URIScheme $scheme_obj
75 public function register($scheme, $scheme_obj)
77 $this->schemes[$scheme] = $scheme_obj;
81 // vim: et sw=4 sts=4